Variance estimation method of random groups in Warner model

In the Warner model,the proportion of the estimated total amount of sensitive attribute is AW=m/n-(1-P)2P-1,variance estimator of AW is υ(AW)=m/n-(1-m/n)(n-1)(2P-1)2;using the variance estimation method of random groups,an unbiased estimator of V(AW) is obtained and then V(AW) was compared with V(^πAW).